#define  _CRT_SECURE_NO_WARNINGS 1

#include <stdio.h>

float max3(float a, float b, float c)
{
    if (a > b && a > c)
    {
        return a;
    }
    else if (b > a && b > c)
    {
        return b;
    }
    else if (c > a && c > b)
    {
        return c;
    }
    else
    {
        return a;
    }

}
int main()
{
    float a = 0, b = 0, c = 0;
    scanf("%f %f %f", &a, &b, &c);
    float X = max3(a + b, b, c) / (max3(a, b + c, c) + max3(a, b, b + c));
    printf("%.2f", X);

    return 0;
}